1. Field of the Invention
The present invention relates to a semiconductor light-emitting device and to a method for manufacturing such a device, and, in particular, to the shape of an envelope for enclosing the semiconductor light-emitting device.
2. Description of the Prior Art
A manufacturing process for a conventional semiconductor light-emitting device will now be explained.
FIG. 1, FIGS. 2A and 2B, FIGS. 3A and 3B, and FIGS. 4A, 4B are diagrams illustrating this manufacturing process.
FIG. 1 is a diagram showing a plurality of semiconductor light-emitting elements mounted on and bonded to a lead frame.
FIG. 2A is a view of the upper surface of an envelope adjusting jig.
FIG. 2B is a longitudinal cross-section viewed along the line IIB–IIB′ in FIG. 2A.
FIG. 3A is an upper surface view showing conditions after shape of the envelopes. FIG. 3B is a longitudinal cross-section viewed along the line IIIB–IIIB′ in FIG. 3A.
FIG. 4A is a view of the upper surface of a completed conventional semiconductor light-emitting device. FIG. 4B is a longitudinal cross-section viewed along the line IVB–IVB′ in FIG. 4A.
In FIG. 1, the reference numeral 8 designates a lead frame. A lead group made up of a pair of leads 9, 9′ is formed at a uniform spacing in the longitudinal direction of the lead frame 8. For example, the uniform spacing between adjacent lead groups is approximately 6 to 7 mm and the leads 9, 9′ are made up of Fe wires.
In FIG. 2A, the reference numeral 12 designates an envelope adjusting jig. A plurality of cavities 13 with circular lateral cross-sections and almost U-shaped longitudinal cross-sections is positionally arranged in a straight line at the same spacing as the lead groups on the lead frame.
First of all, as shown in FIG. 1, a semiconductor light-emitting element 10 is mounted on the upper end of one of the leads 9 in each of the lead groups on the lead frame 8. The upper surface of the semiconductor light-emitting element 10 and the other lead 9′ are electrically connected by a bonding wire 11.
Next, a light-transmitting resin such as a liquid mixture of epoxy resin, the leis filled into the cavities 13 of the envelope adjusting jig 12 shown in FIGS. 2A and 2B, then the lead groups of the lead frame 8 are inserted into the respective cavities 13 and the light-transmitting resin is thermally cured.
As shown in FIGS. 3A and 3B, the mounted section of the semiconductor light-emitting element 10 of the lead groups and the upper end section of the bonding wire 11 and the leads 9, 9′ are sealed in an envelope 14 formed by the light-transmitting resin. Subsequently, as shown in FIGS. 4A and 4B, each of the lead groups is separated from the lead frame 8 at the part shown by the broken lines in FIG. 3B with a cutter to complete the semiconductor light-emitting device.
Recently, there have been demands for semiconductor light-emitting devices with a high output. Also, it is commonly known that the diameter 14D of the light-emitting device 14 should be made as large as possible to successfully obtain high output.
However, for good production efficiency in this manufacturing method for the conventional semiconductor light-emitting device, the spacing between the lead groups is set so that it is possible to form about 10 to 30 semiconductor light-emitting devices using one lead frame, and, in addition, the diameter 13D of the envelope depends on the spacing of the lead groups on the lead frame. For this reason, there is the problem that even when it is desired to increase the diameter of the envelope to obtain high output, this diameter is limited by the spacing of the lead groups. In addition, when the spacing of the lead groups is increased to provide an envelope with a large diameter, the number of semiconductor light-emitting devices obtained from one lead frame is reduced. This results in the problem of poor production efficiency.